Introduction; Configuration - Draytek Vigor2500V Manual

Prevention of Denial of Service
A.1 Introduction
The DoS Defense functionality helps you to detect and mitigate the DoS
attacks. Those attacks include the flooding-type attacks and the
vulnerability attacks. The flooding-type attacks attempt to use up all your
system' s resource while the vulnerability attacks try to paralyze the system
by offending the vulnerabilities of the protocol or operation system.
A.2 An Overview of DoS Defense Functionality
The DoS Defense Engine inspects each incoming packet against the
attack signature database. Any packet that may paralyze the host in the
security zone is blocked and a syslog message is sent to the client. Also
the DoS Defense Engine monitors the traffic behavior. Any anomaly
situation violating the administrator' s configuration is reported and the
corresponding defense function is performed in order to mitigate the
attack.
A.3 Configuration
The following sections will explain in more detail about DoS Defense
Setup by using the Web Configurator. It is a sub-functionality of IP
Filter/Firewall. There are a total of 15 kinds of defense function for the
DoS Defense Setup. By default, the DoS Defense functionality is disabled.
Further, once the DoS Defense functionality is enabled, the default values
for the threshold and timeout values existing in some functions are set to
Firewall
Supplement A
6-11
Attacks